Kawasaki 15hp oil capacity

Hello all, i have a mower with a 15hp Kawasaki, the owner's manual says 60oz is the capacity for oil. When i drain, replace filter, and refill 60oz sometimes it will be overfilled. Are you supposed to allow for an ounce or two that simply didn't drain out of the engine? Also, when changing the oil and not replacing the filter, how much oil should be refilled into the engine. Thanks for any help.

Not sure if there is any difference, my 15hp kawa is 2 years old and on a toro walkbehind and it holds 52 oz with a filter change. If the mower is setting not level it is possable for an ounce or so to be left in the engine, and its easy to be off a lil also when tring to get exactly 28oz out of the 2nd bottle of oil too